Add InfoBox to QuantumTape and Update typehints (#6114)

**Context:**
Differences between `QuantumTape` and `QuantumScript` need to be
emphasized more explicitly in the docs due to significant performance
differences.

**Description of the Change:**
- Added a `Note` box to the `QuantumTape` page, instructing users to use
`QuantumScript` if performance is a concern.
- Added `QuantumScriptBatch` as a counterpart to `QuantumTapeBatch`
- Updated relevant typehints to use `QuantumScript` and
`QuantumScriptBatch` instead.

**Benefits:**
- Better UX.

**Possible Drawbacks:**
- More confusion (?)

[[sc-22442](https://app.shortcut.com/xanaduai/story/22442)]

doc/code/qml_tape.rst

@@ -18,6 +18,8 @@ TensorFlow, and PyTorch.
     details on creating QNodes, as well as the :func:`~pennylane.qnode` decorator
     and :func:`~pennylane.QNode` constructor.
 
+.. _tape-vs-script:
+
 QuantumTape versus QuantumScript
 --------------------------------
 
@@ -66,6 +68,6 @@ and a reduction in unintended side effects, ``QuantumScript`` is strictly used i
 
 .. automodapi:: pennylane.tape
     :no-main-docstr:
+    :skip: QuantumTapeBatch, QuantumScriptBatch
     :include-all-objects:
-    :skip: QuantumTapeBatch
     :inheritance-diagram:

pennylane/debugging/snapshot.py

@@ -18,7 +18,7 @@
 from functools import partial
 
 import pennylane as qml
-from pennylane.tape import QuantumTape, QuantumTapeBatch
+from pennylane.tape import QuantumScript, QuantumScriptBatch
 from pennylane.transforms import transform
 from pennylane.typing import PostprocessingFn
 
@@ -56,7 +56,7 @@ def __exit__(self, exc_type, exc_value, exc_traceback):
 
 
 @transform
-def snapshots(tape: QuantumTape) -> tuple[QuantumTapeBatch, PostprocessingFn]:
+def snapshots(tape: QuantumScript) -> tuple[QuantumScriptBatch, PostprocessingFn]:
     r"""This transform processes :class:`~pennylane.Snapshot` instances contained in a circuit,
     depending on the compatibility of the execution device.
     For supported devices, the snapshots' measurements are computed as the execution progresses.

pennylane/devices/_legacy_device.py

@@ -38,7 +38,7 @@
 from pennylane.operation import Observable, Operation, Operator, StatePrepBase, Tensor
 from pennylane.ops import Hamiltonian, LinearCombination, Prod, SProd, Sum
 from pennylane.queuing import QueuingManager
-from pennylane.tape import QuantumScript, QuantumTape, expand_tape_state_prep
+from pennylane.tape import QuantumScript, expand_tape_state_prep
 from pennylane.wires import WireError, Wires
 
 
@@ -720,7 +720,7 @@ def expand_fn(self, circuit, max_expansion=10):
 
         return self.default_expand_fn(circuit, max_expansion=max_expansion)
 
-    def batch_transform(self, circuit: QuantumTape):
+    def batch_transform(self, circuit: QuantumScript):
         """Apply a differentiable batch transform for preprocessing a circuit
         prior to execution. This method is called directly by the QNode, and
         should be overwritten if the device requires a transform that

pennylane/devices/_qubit_device.py

@@ -54,7 +54,7 @@
 )
 from pennylane.operation import Operation, operation_derivative
 from pennylane.resource import Resources
-from pennylane.tape import QuantumTape
+from pennylane.tape import QuantumScript
 from pennylane.wires import Wires
 
 from ._legacy_device import Device
@@ -360,7 +360,7 @@ def execute(self, circuit, **kwargs):
 
         return results
 
-    def shot_vec_statistics(self, circuit: QuantumTape):
+    def shot_vec_statistics(self, circuit: QuantumScript):
         """Process measurement results from circuit execution using a device
         with a shot vector and return statistics.
 
@@ -438,7 +438,7 @@ def shot_vec_statistics(self, circuit: QuantumTape):
 
         return tuple(results)
 
-    def _multi_meas_with_counts_shot_vec(self, circuit: QuantumTape, shot_tuple, r):
+    def _multi_meas_with_counts_shot_vec(self, circuit: QuantumScript, shot_tuple, r):
         """Auxiliary function of the shot_vec_statistics and execute
         functions for post-processing the results of multiple measurements at
         least one of which was a counts measurement.
@@ -611,7 +611,7 @@ def _measure(
         )
 
     def statistics(
-        self, circuit: QuantumTape, shot_range=None, bin_size=None
+        self, circuit: QuantumScript, shot_range=None, bin_size=None
     ):  # pylint: disable=too-many-statements
         """Process measurement results from circuit execution and return statistics.
 
@@ -1623,7 +1623,7 @@ def sample(self, observable, shot_range=None, bin_size=None, counts=False):
         )
 
     def adjoint_jacobian(
-        self, tape: QuantumTape, starting_state=None, use_device_state=False
+        self, tape: QuantumScript, starting_state=None, use_device_state=False
     ):  # pylint: disable=too-many-statements
         """Implements the adjoint method outlined in
         `Jones and Gacon <https://arxiv.org/abs/2009.02823>`__ to differentiate an input tape.
@@ -1778,7 +1778,7 @@ def _adjoint_jacobian_processing(jac):
         # must be 2-dimensional
         return tuple(tuple(np.array(j_) for j_ in j) for j in jac)
 
-    def _get_diagonalizing_gates(self, circuit: QuantumTape) -> list[Operation]:
+    def _get_diagonalizing_gates(self, circuit: QuantumScript) -> list[Operation]:
         """Returns the gates that diagonalize the measured wires such that they
         are in the eigenbasis of the circuit observables.
 

pennylane/devices/default_clifford.py

@@ -39,7 +39,7 @@
     VnEntropyMP,
 )
 from pennylane.ops.qubit.observables import BasisStateProjector
-from pennylane.tape import QuantumTape, QuantumTapeBatch
+from pennylane.tape import QuantumScript, QuantumScriptBatch
 from pennylane.transforms import convert_to_numpy_parameters
 from pennylane.transforms.core import TransformProgram
 from pennylane.typing import Result, ResultBatch
@@ -497,7 +497,7 @@ def preprocess(
 
     def execute(
         self,
-        circuits: Union[QuantumTape, QuantumTapeBatch],
+        circuits: Union[QuantumScript, QuantumScriptBatch],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ) -> Union[Result, ResultBatch]:
         max_workers = execution_config.device_options.get("max_workers", self._max_workers)

pennylane/devices/default_qubit.py

@@ -28,7 +28,7 @@
 from pennylane.logging import debug_logger, debug_logger_init
 from pennylane.measurements.mid_measure import MidMeasureMP
 from pennylane.ops.op_math.condition import Conditional
-from pennylane.tape import QuantumTape, QuantumTapeBatch
+from pennylane.tape import QuantumScript, QuantumScriptBatch, QuantumScriptOrBatch
 from pennylane.transforms import convert_to_numpy_parameters
 from pennylane.transforms.core import TransformProgram
 from pennylane.typing import PostprocessingFn, Result, ResultBatch
@@ -53,8 +53,6 @@
 logger = logging.getLogger(__name__)
 logger.addHandler(logging.NullHandler())
 
-QuantumTape_or_Batch = Union[QuantumTape, QuantumTapeBatch]
-
 
 def stopping_condition(op: qml.operation.Operator) -> bool:
     """Specify whether or not an Operator object is supported by the device."""
@@ -166,8 +164,8 @@ def all_state_postprocessing(results, measurements, wire_order):
 
 @qml.transform
 def adjoint_state_measurements(
-    tape: QuantumTape, device_vjp=False
-) -> tuple[QuantumTapeBatch, PostprocessingFn]:
+    tape: QuantumScript, device_vjp=False
+) -> tuple[QuantumScriptBatch, PostprocessingFn]:
     """Perform adjoint measurement preprocessing.
 
     * Allows a tape with only expectation values through unmodified
@@ -483,7 +481,7 @@ def __init__(
     def supports_derivatives(
         self,
         execution_config: Optional[ExecutionConfig] = None,
-        circuit: Optional[QuantumTape] = None,
+        circuit: Optional[QuantumScript] = None,
     ) -> bool:
         """Check whether or not derivatives are available for a given configuration and circuit.
 
@@ -614,7 +612,7 @@ def _setup_execution_config(self, execution_config: ExecutionConfig) -> Executio
     @debug_logger
     def execute(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ) -> Union[Result, ResultBatch]:
         self.reset_prng_key()
@@ -669,7 +667,7 @@ def execute(
     @debug_logger
     def compute_derivatives(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
         max_workers = execution_config.device_options.get("max_workers", self._max_workers)
@@ -689,7 +687,7 @@ def compute_derivatives(
     @debug_logger
     def execute_and_compute_derivatives(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
         self.reset_prng_key()
@@ -713,7 +711,7 @@ def execute_and_compute_derivatives(
     def supports_jvp(
         self,
         execution_config: Optional[ExecutionConfig] = None,
-        circuit: Optional[QuantumTape] = None,
+        circuit: Optional[QuantumScript] = None,
     ) -> bool:
         """Whether or not this device defines a custom jacobian vector product.
 
@@ -732,7 +730,7 @@ def supports_jvp(
     @debug_logger
     def compute_jvp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         tangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
@@ -752,7 +750,7 @@ def compute_jvp(
     @debug_logger
     def execute_and_compute_jvp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         tangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
@@ -781,7 +779,7 @@ def execute_and_compute_jvp(
     def supports_vjp(
         self,
         execution_config: Optional[ExecutionConfig] = None,
-        circuit: Optional[QuantumTape] = None,
+        circuit: Optional[QuantumScript] = None,
     ) -> bool:
         """Whether or not this device defines a custom vector jacobian product.
 
@@ -800,7 +798,7 @@ def supports_vjp(
     @debug_logger
     def compute_vjp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         cotangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
@@ -868,7 +866,7 @@ def _state(circuit):
     @debug_logger
     def execute_and_compute_vjp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         cotangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):

pennylane/devices/default_qubit_legacy.py

@@ -1099,7 +1099,7 @@ def classical_shadow(self, obs, circuit):
 
         return self._cast(self._stack([outcomes, recipes]), dtype=np.int8)
 
-    def _get_diagonalizing_gates(self, circuit: qml.tape.QuantumTape) -> list[Operation]:
+    def _get_diagonalizing_gates(self, circuit: qml.tape.QuantumScript) -> list[Operation]:
         meas_filtered = [
             m
             for m in circuit.measurements

pennylane/devices/default_qutrit_mixed.py

@@ -25,7 +25,7 @@
 import pennylane as qml
 from pennylane.logging import debug_logger, debug_logger_init
 from pennylane.ops import _qutrit__channel__ops__ as channels
-from pennylane.tape import QuantumTape, QuantumTapeBatch
+from pennylane.tape import QuantumScript, QuantumScriptOrBatch
 from pennylane.transforms.core import TransformProgram
 from pennylane.typing import Result, ResultBatch
 
@@ -46,9 +46,6 @@
 logger = logging.getLogger(__name__)
 logger.addHandler(logging.NullHandler())
 
-Result_or_ResultBatch = Union[Result, ResultBatch]
-QuantumTape_or_Batch = Union[QuantumTape, QuantumTapeBatch]
-
 
 observables = {
     "THermitian",
@@ -293,7 +290,7 @@ def __init__(  # pylint: disable=too-many-arguments
     def supports_derivatives(
         self,
         execution_config: Optional[ExecutionConfig] = None,
-        circuit: Optional[QuantumTape] = None,
+        circuit: Optional[QuantumScript] = None,
     ) -> bool:
         """Check whether or not derivatives are available for a given configuration and circuit.
 
@@ -388,9 +385,9 @@ def preprocess(
     @debug_logger
     def execute(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
-    ) -> Result_or_ResultBatch:
+    ) -> Union[Result, ResultBatch]:
         interface = (
             execution_config.interface
             if execution_config.gradient_method in {"best", "backprop", None}

pennylane/devices/default_tensor.py

@@ -43,14 +43,12 @@
 )
 from pennylane.operation import Observable, Operation, Tensor
 from pennylane.ops import LinearCombination, Prod, SProd, Sum
-from pennylane.tape import QuantumScript, QuantumTape, QuantumTapeBatch
+from pennylane.tape import QuantumScript, QuantumScriptOrBatch
 from pennylane.templates.subroutines.trotter import _recursive_expression
 from pennylane.transforms.core import TransformProgram
 from pennylane.typing import Result, ResultBatch, TensorLike
 from pennylane.wires import WireError
 
-QuantumTape_or_Batch = Union[QuantumTape, QuantumTapeBatch]
-
 has_quimb = True
 
 warnings.filterwarnings("ignore", message=".*kahypar")
@@ -624,7 +622,7 @@ def preprocess(
 
     def execute(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ) -> Union[Result, ResultBatch]:
         """Execute a circuit or a batch of circuits and turn it into results.
@@ -829,7 +827,7 @@ def supports_derivatives(
 
     def compute_derivatives(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
         """Calculate the Jacobian of either a single or a batch of circuits on the device.
@@ -847,7 +845,7 @@ def compute_derivatives(
 
     def execute_and_compute_derivatives(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
         """Compute the results and Jacobians of circuits at the same time.
@@ -867,7 +865,7 @@ def execute_and_compute_derivatives(
     def supports_vjp(
         self,
         execution_config: Optional[ExecutionConfig] = None,
-        circuit: Optional[QuantumTape] = None,
+        circuit: Optional[QuantumScript] = None,
     ) -> bool:
         """Whether or not this device defines a custom vector-Jacobian product.
 
@@ -882,7 +880,7 @@ def supports_vjp(
 
     def compute_vjp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         cotangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):
@@ -904,7 +902,7 @@ def compute_vjp(
 
     def execute_and_compute_vjp(
         self,
-        circuits: QuantumTape_or_Batch,
+        circuits: QuantumScriptOrBatch,
         cotangents: tuple[Number, ...],
         execution_config: ExecutionConfig = DefaultExecutionConfig,
     ):